Unit 3 Notes

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School

University of Guelph

Department

Biology

Course

BIOL 1070

Professor

T.Ryan Gregory

Semester

Winter

Description

Adaptation and Specializationy Diversity and wellsuited life in habitat are result of evolution o Diversity is due to generation of diversity and long periods of evolution by natural selection y Evolution comes in different forms o Natural selection o Mutationnew genetic variation o Genetic driftchanges through chance o Gene flowmovement of genesy Natural selection is nonrandom only one that results in the evolution of adaptationsNatural selection Nonrandom differences in survival andor reproduction among individual entities on the basis of differences in heritable characteristics Adaptation 1 A characteristic that enhances the survival andor reproduction of organisms that bear it relative to alternative especially ancestral character states 2 a physical physiological behavioural or other characteristic evolved through natural selection NOT the change undergone by an individual organism during its lifetime in response to external conditions Population for sexual species a group of interbreeding individuals and their offspring Alleles alternate forms of a geneThe Basis of Natural SelectionOrigin of SpeciesDarwin y 2 major objectives o Provide convincing evidence species are related through common ancestryo Are to argue his mechanism of natural selection could account for changed through time and the resulting differences among species y 2 problems o Possible species are related by common descent but natural selection is not dominantbut natural selection is the only scientific explanation for adaptive changes among species and how they survive successfulo He references artificial selectionselection by a human breeder natural selection does NOT involve choice by any particular agent no one looking at the best option so how does it occur Natural selection is the logical outcome of these postulates Darwin presented them 1 Individuals within populations are variablenot every individual is identical in a population